Proposals for driving military track vehicles by an electrical transmission commonly suggest the use of a single generator that powers two electric motors--one motor being operatively connected to the track on one side of the vehicle and the other motor being operatively connected to the track on the other side of the vehicle.
In such an arrangement, the electrical power to drive the vehicle would be provided by an on-board engine-generator combination. The electrical power provided by the engine-generator combination would be delivered to the motors which convert the electrical energy into rotary mechanical energy to drive the vehicle. Alternatively, such a drive system might use a single motor geared to each output. In either situation, the motor with its associated gearing, must be able to generate the maximum torque required of the vehicle and must also be able to drive the vehicle at the maximum output speed desired therefor. Although the power generating source is not required to provide sufficient power to drive the motor or motors at maximum speed with maximum torque, these parameters do define the size of the motor(s) required. Specifically, the product of the desired maximum speed and the required maximum torque defines the "Corner Horsepower" of the motor, and thus controls the size required.
When using a single motor to drive each track of a track-laying vehicle, the two motors are independently controlled such that the vehicle moves in a straight manner when the speeds of the motors are equal, and the vehicle is steered when the speeds of the two motors are independently varied. When using only a single motor to drive both tracks of the track-laying vehicle, the gearing by which the single motor is operatively connected to the two tracks must accommodate the independent speed control required to effect both straight line movement and the steering movement.
During a turn in either direction, one track becomes the inner track (relative to the turn), and the other track becomes the outer track. A major drawback of this arrangement is the requirement that the vehicle be capable of delivering full torque to either of its two tracks. This requires that either the single motor arrangement or the two-motor arrangement, and the attendant engine-generator be capable of providing maximum torque and maximum speed to each track. However, during most maneuvers of the vehicle, half the output need be delivered to each track so that whichever number of motors are employed, only half the rated capacity of the motors need be delivered to each track.